CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 102,544	$ 102,176
Accounts receivable, net of allowance for doubtful accounts of $2,188 and $2,402, respectively	128,407	116,947
Contract assets	22,756	32,403
Inventories	88,226	78,996
Taxes receivable	12,687	6,652
Prepaid expenses	5,066	4,870
Other current assets	7,986	7,348
Assets of a business held-for-sale	1,233	0
Total current assets	368,905	349,392
Property, plant and equipment, at cost	515,393	506,509
Accumulated depreciation	(303,908)	(291,996)
Property, plant and equipment, net	211,485	214,513
Operating lease right-of-use assets	25,798	22,243
Goodwill	87,842	87,595
Other intangible assets, net	86,922	95,121
Other assets, net	6,948	6,598
Total assets	787,900	775,462
Current liabilities:
Current portion of long-term debt	8,609	9,789
Accounts payable	116,631	101,905
Accrued payroll and other compensation	23,177	24,589
Accrued taxes	6,555	8,214
Derivative liabilities	8,147	11,996
Restructuring liabilities	36	9,431
Other accrued liabilities	24,442	21,705
Liabilities of a business held-for-sale	1,933	0
Total current liabilities	189,530	187,629
Long-term debt	251,477	260,649
Long-term operating lease liabilities	20,973	17,947
Deferred tax liabilities	30,913	27,174
Benefit plan liabilities	17,554	21,691
Other long-term liabilities	2,254	2,676
Commitments and Contingencies (Note 16)
Stockholders' equity:
Preferred stock, $0.01 per share par value, 500 shares authorized (none issued or outstanding)	0	0
Common stock, $0.01 per share par value, 30,000 shares authorized (25,755 and 25,555 shares issued, respectively)	258	256
Capital in excess of par value	103,272	99,770
Retained earnings	277,778	266,904
Accumulated other comprehensive income (loss)	(15,016)	(18,342)
Less treasury stock, 7,722 and 7,717 shares of common stock, respectively, at cost	(91,093)	(90,892)
Total stockholders' equity	275,199	257,696
Total liabilities and stockholders’ equity	$ 787,900	$ 775,462